Structural predictions of superconducting phase in tungsten ditellurides WTe2 from first-principles evolutionary techniques under high pressure

Abstract

High-pressure phases of WTe2 are investigated by using first-principles evolutionary algorithm technique. The novel monoclinic (C2/m) and tetragonal (I4/mmm) phases of WTe2 are found to be thermodynamically stable, as the material is compressed under the applied pressure above 80 GPa. Because of their substantial similarity in terms of enthalpy and several intrinsic properties, the two novel high-pressure phases are likely to coexist in practical samples of WTe2. By inspecting their electronic band structures, both C2/m and I4/mmm phases are likely type-II Weyl semimetal, and by using the Allen-Dynes equation we find that the two phases also behave conventional Bardeen-Cooper-Schrieffer superconductors. The electron localized solutions and the nature of the chemical bonding in WTe2 further support the superconducting transition temperature in the proposed C2/m and I4/mmm phases.